PH concerns

[bertden]

I never bothered with the PH before. But this time I was curious and I tested the PH before (5.2) and during fermentation (3.78, 48 hours after pitching). So, how low is too low? I know it should be around 4.0-4.2 after fermentation but is 3.78 too low and I should make adjustments in future brews or just let it be?

Thanks

 

[Bassman2003]

Testing pH is finicky. If you do not do it a lot, it is tough to trust the measurement. 1) The meter needs to be calibrated with fresh, in-spec calibration solution. 2) Is the meter's probe in good condition? 3) Is the meter good enough? 4) If you are using strips they are tough to trust as well.

Having said all of that, pH 3.78 for finished beer is concerning for infection.

 

[ClaudiusB]

I never bothered with the PH before. But this time I was curious and I tested the PH before (5.2) and during fermentation (3.78, 48 hours after pitching). So, how low is too low? I know it should be around 4.0-4.2 after fermentation but is 3.78 too low and I should make adjustments in future brews or just let it be?

Thanks

I measure the pH during fermentation all the time. The pH drop I observe is yeast-dependent, as well as bottom versus top fermenting. The top-fermenting yeast always has a lower endpoint compared to the bottom-fermenting yeast.
My Kölsch yeast started at pH 5.09, 1st day 4.16, 2nd day 3.97, on the 7th day it went up to the final pH 4.13. The pH rises the more dead cells increases in the solution.
My Maibock yeast started at pH 5.35, 1st day 5.048, second day 4.854, final pH 4.35.
I have seen wheat beer yeast go below pH 4.
My yeast strains are all liquid.

What is the accuracy of your pH meter and calibration solution?

 

[bertden]

Testing pH is finicky. If you do not do it a lot, it is tough to trust the measurement. 1) The meter needs to be calibrated with fresh, in-spec calibration solution. 2) Is the meter's probe in good condition? 3) Is the meter good enough? 4) If you are using strips they are tough to trust as well.

Having said all of that, pH 3.78 for finished beer is concerning for infection.

Thanks I will re-calibrate my PH meter just in case. For some context this is a low ABV (2.5-3.0) brew that included 100 gr of acidulated malt in a pretty small grain bill, currently fermenting in a keg. Hopefully it's not infected. Guess I will find out in a few days.

 

[bertden]

I measure the pH during fermentation all the time. The pH drop I observe is yeast-dependent, as well as bottom versus top fermenting. The top-fermenting yeast always has a lower endpoint compared to the bottom-fermenting yeast.
My Kölsch yeast started at pH 5.09, 1st day 4.16, 2nd day 3.97, on the 7th day it went up to the final pH 4.13. The pH rises the more dead cells increases in the solution.
My Maibock yeast started at pH 5.35, 1st day 5.048, second day 4.854, final pH 4.35.
I have seen wheat beer yeast go below pH 4.
My yeast strains are all liquid.

What is the accuracy of your pH meter and calibration solution?

Thanks. I'm new to using a PH meter, I will re-calibrate and re-test. By the way it is a low ABV wheat bear using probably a bit too much flaked oats and acidulated malt currently fermenting using the W-68 yeast.

 

[Bassman2003]

If it is a hefe you might be ok. Let us know after you calibrate the meter. I was shocked to learn the calibration solution makes a big difference and only is good for a year or so. I have moved to some tablets I found on Ebay for longer storage life.

 

[bertden]

If it is a hefe you might be ok. Let us know after you calibrate the meter. I was shocked to learn the calibration solution makes a big difference and only is good for a year or so. I have moved to some tablets I found on Ebay for longer storage life.

Actually it is, more or less. I brew like I cook or bake, not one to follow recipe to the letter.

 

[jerrylotto]

pH is critical to mashing, should be between 5.3 and 5.6. It is less important for fermentation. I wouldn't worry too much

 

[ClaudiusB]

pH is critical to mashing, should be between 5.3 and 5.6. It is less important for fermentation. I wouldn't worry too much

Gathering data is crucial at every stage of brewing. It helps with troubleshooting, consistency, and it's fun.
Fermentation pH analysis is a good indication of fermentation.
Kara Taylor, White Labs' head of laboratory operations, recommends collecting at least six pH data points throughout the fermentation process.

 

[MaxStout]

I've never tested pH during fermentation, but might start doing so, just to keep tabs on the process. Do you let the samples outgas the dissolved CO2 before measuring?

 

[ClaudiusB]

I've never tested pH during fermentation, but might start doing so, just to keep tabs on the process. Do you let the samples outgas the dissolved CO2 before measuring?

I let the sample sit for 15-30 minutes until the foam disappears.

 

[HighVoltageMan!]

Final beer pH is yeast strain dependent. The important part often missed by home brewers is the pH at pitch. Typically it should be 5.05-5-2 for light beers and 5.2-5.3 for darker beers. The pitch pH sets up fermentation so the yeast can hit it's typical pH at FG.

Lagers almost always hit a pH @ 4.3 or so. US05 (Chico) strains are 4.3-4.5. Some English strains can drop a little lower @ 4.2-4.3. Kolsch strains tend to be the lowest with 2565 @ 4.1-4.2 and WLP @ 3.9-4.0.

Dry hopping will cause the pH to rise depending on hop load. All pH measurements should be made with flat or still beer. The carbonation can be removed by straining the beer through a paper towel or just pouring it from one glass to the another until it's flat. This helps with consistency in measuring because you will reduce the carbonic acid from the co2 and the pH probe won't have co2 bubbles clinging to the probe and changing the readings.